Fatal build error: json.cpp: assigning to 'PSZ' (aka 'char *') from incompatible type 'const char *'

$ clang --version

Apple LLVM version 7.0.2 (clang-700.1.81)

Target: x86_64-apple-darwin15.3.0

Thread model: posix

[ 82%] Building CXX object storage/connect/CMakeFiles/connect.dir/json.cpp.o

cd /tmp/mariadb20151224-2853-1xebbq2/mariadb-10.1.10/storage/connect && /usr/local/Library/ENV/4.3/clang++   -DFORCE_INIT_OF_VARS -DHAVE_CONFIG_H -DHUGE_SUPPORT -DLIBXML2_SUPPORT -DLINUX -DMARIADB -DMYSQL_DYNAMIC_PLUGIN -DPIVOT_SUPPORT -DUBUNTU -DUNIX -DXMAP -DZIP_SUPPORT -Dconnect_EXPORTS -I/tmp/mariadb20151224-2853-1xebbq2/mariadb-10.1.10/include -I/tmp/mariadb20151224-2853-1xebbq2/mariadb-10.1.10/sql -I/usr/include/libxml2 -I/usr/local/opt/openssl/include  -pie -fPIC -fstack-protector --param=ssp-buffer-size=4 -DWITH_INNODB_DISALLOW_WRITES -fno-exceptions -fno-rtti -fpermissive -fexceptions -fPIC  -O2 -g -DNDEBUG -D_FORTIFY_SOURCE=2 -DDBUG_OFF -fPIC   -Wall -Wmissing-declarations -Wno-write-strings -Wno-unused-variable -Wno-unused-value -Wno-unused-function -Wno-parentheses -o CMakeFiles/connect.dir/json.cpp.o -c /tmp/mariadb20151224-2853-1xebbq2/mariadb-10.1.10/storage/connect/json.cpp

/tmp/mariadb20151224-2853-1xebbq2/mariadb-10.1.10/storage/connect/json.cpp:597:7: error: assigning to 'PSZ' (aka 'char *') from incompatible type 'const char *'

                str = (err) ? NULL : "Ok";

                    ^ ~~~~~~~~~~~~~~~~~~~

1 error generated.

make[2]: *** [storage/connect/CMakeFiles/connect.dir/json.cpp.o] Error 1

make[2]: *** Waiting for unfinished jobs....